The sequence of some regular proteins, together with other structural information such as data from x-ray diffraction, fiber diffraction, electron microscopy, and spectroscopic analysis can be used to evaluate models of the protein structure. Two current studies involve keratin (with NIADDK and NCI) and actin (with NIADDK). As the sequence of keratin cyanogen bromide fragments becomes available, an analysis of the sequence is proceeding by studying the periodicities in the sequence, and by predicting by computer the conformational properties of the specific amino acids in local regions of the chain. It is anticipated that the experimental results may be able to clearly specify if any of the proposed two or three models are correct.